Control mechanism for core blowers



Aug. 21, 1956 A. v. MAGNUSON ETAL 2,759,229

CONTROL MECHANISM FOR CORE BLOWERS Filed NOV. 29, 1951 6 Sheets-Sheet l a a 4% omwms Wm Aug. 21, 1956 A. v. mAsNuwN ETAL 2,7

CONTROL MECHANISM FOR CORE BLOWERS Filed NOV. 29, 1951 6 Shee'ts-Sheet 2 F0 RWA R a HOPPER Aug. 21, 1956 A. v. MAGNUSON ETAL 2,759,229

CONTROL MECHANISM FOR CORE BLOWERS 6 Sheets-Sheet 3 Filed Nov. 29, 1951 W NQN JOUPIOU L EIJ U AN NR O llav-onu NNN mmmmQI Aug. 21, 1956 A. v. MAGNUSON ETAL 2,759,229

CONTROL MECHANISM FOR CORE BLOWERS e Sheets-Shet 4 Filed Nov. 29, 1951 zoF uwao gm Q? 7'6 fa avv/a NRN Aug. 21, 1956 A. v. MEI-SON ITI'AL 2,759,229

CUNTROL MECHANIESM FOR CORE BLOWERS Filed Nov. 29, 1951 6 Sheets-Sheet 5 142 15643 f 1 j I 7 '5.

I 120 I v 42 v 150 f 1/9 ji yfl Q/ azaaw/a Aug. 21, 1956 A. v. MAGNUSON ETAL CONTROL MECHANISM FOR com: BLOWEIRS 6 Sheets-Sheet 6 Filed Nov. 29, 1951 O-OZNJOm United States Patent CONTROL MECHANISM FOR CORE BLOWERS Alfred V. Magnuson, Rockford, and Adam Kafka, Chicago, Ill., assignors, by mesne assignments, to Pettibone Mulllken Corporation, a corporation of Delaware Application November 29, 1951, Serial No. 258,946

7 Claims. (Cl. 22-10) The present invention relates generally to a mechanism for controlling the operation of a plurality of elements having relative movement in a certain sequence and more particularly to an operating mechanism for controlling the movements of a core-making machine in which sand is blown into a core-box, mold, or form.

Core-making machines are usually provided with an air chamber and a movable sand transfer member which carries a charge of sand at least suflicient to make the core from a supply hopper to a position in alignment with and between the air chamber and the core-box or mold. The core-box or mold is usually supported on a table or platform that is raised by a pneumatic lift to carry the core-box into tight engagement with the lower end of the sand transfer member and force the upper end of the latter into tight engagement with the air discharge port of the air chamber. From the sand transfer member, the sand is blown into the core-box and packed therein by the air and sand under pressure. The table or platform is then lowered and the core removed.

For a particular job, it may be necessary to make either a few or a great multiplicity of cores. If it is necessary to make only a few cores, it is desirable to be able to manually control the operations of the core-making machine so as to regulate the timing in accordance with the requirements of the particular core-box being used. However, when one wants to make a great many identical cores, it is desirable to be able to automatically control the operation of the core-making machine so as to save labor, increase the speed of operation of the machine, and eliminate any human inaccuracies which might alter the uniformity of the cores being made. Since the timing operations of a core-making machine must be adjusted in accordance with the core-box being used, a certain amount of time is required to set a core-making machine for automatic use. In addition, if the cores being made require only a fraction of the sand carried by the sand chamber, it is desirable to be able to manually control the movement of the sand transfer member between the sand hopper and the air chamber and to automatically control the other operations of the core-making machine. When a core-making machine is controlled in this manner, the sand transfer member can be kept in alignment With the air chamber while automatically making a group of cores, that is, until this sand in the sand transfer member becomes depleted.

The objects of this invention are: to provide a particularly simple, compact, and easily operable control mechanism for effecting the movements of the operating mechanisms of a core-making machine in a predetermined sequence; to provide an improved control mechanism for a core-making machine for elfecting the movements of the operating mechanisms of the machine in a predetermined sequence in either a manual, automatic, or semi-automatic manner; to provide improved safety features for a core-making machine which prevent the operating mechanisms of the machine from moving out of their proper sequence; and to provide an improved core- Patented Aug. 21, 1956 making machine which is simple in construction, easily adjustable for difierent types of work, and quick and convenient in operation. I

Still further objects and attendant advantages of the Invention will be apparent to persons skilled in the art from the following detailed description of an approved embodiment of the invention shown in the accompanying drawings, in which:

Fig. 1 is a vertical sectional view of a core-making machine constructed in accordance with the present invention;

Fig. 2 is a diagrammatic view of the air lines and control valves for the core-making machine shown in Fig. l with the selector valves and by-pass valves set for manual operation of the machine;

Fig. 3 is a diagrammatic view of the air lines and control valves for the core-making machine with the selector valves and by-pass valves set for automatic operation of the machine;

Fig. 4 is a diagrammatic view of the air lines and control valves for the core-making machine with the selector valves and by-pass valves set for semi-automatic operation of the machine;

Fig. 5 is an enlarged sectional view of the diaphragm valve associated with core-box clamping mechanism of the core-making machine;

Fig. 6 is an enlarged sectional view of the vibrator valve of the core-making machine;

Fig. 7 is an enlarged sectional view of the exhaust valve for the clamping cylinder of the core-making machine;

Fig. 8 is an enlarged sectional view of the exhaust valve for the air chamber of the core-making machine;

Fig. 9 is a sectional view of the diaphragm valve associated with the blowing mechanism of the core-making machine;

Fig. 10 is a diagrammatic view of the electrical means for operating the solenoid valves of the control mechanism of the core-making machine.

General description .The core-making machine illustrated in the drawings includes a sand transfer mechanism, a core-box clamping mechanism, and a blowing mechanism, the mechanisms having a relative movement in a predetermined sequence. The movements of the core-making machine mechanisms are controlled by a means including a plurality of selector valves and by-pass valves which may be adjusted to a plurality of arrangements, a plurality of manually operable control valves which control the movements of the core-making machine mechanisms in sequence when the selector valves and by-pass valves are adjusted to a first arrangement, a plurality of electrically operable control valves which control the movements of the coremaking machine mechanisms in sequence when the selector valves and by-pass valves are adjusted to a second arrangement, and an electric circuit which automatically controls the operation of the electric control valves. In addition, a portion of the manually operable control valves is operable to control the movement of the sand transfer mechanism and a portion of the electrically operable control valves is operable for controlling the corebox clamping mechanism and the blowing mechanism in sequence when the selector valves and bypass valves are adjusted to a third arrangement. Various novel safety features associated with the control means of the coremaking machine prevent the operation of the core-making machine mechanisms out of the predetermined sequence.

Detailed description As shown in Fig. l, the core-making machine com prises a pair of side frames 20 of the general type of a punch press frame spaced substantially mid-height by a U-shaped bar 21, one wall of which merges into the top plate 22 of a base platform 23 that constitutes a support for the core-box lifting and lowering device, later described. Surmounting and bolted to the side frames is a hood 24 that extends rearwardly somewhat beyond the rear of the side frames 20 and itself constituting a support for a sand hopper 25 and a casing 26 for a sand blow valve 27. In the lower portion of the casing 26 is an air chamber 28 having a port 29, which cooperates with a valve piston 30 disposed in a valve chamber 31 above the air chamber 28. The air chamber 28 is of such width as to uniformly distribute the air over the top of the underlying column of sand to be blown. The valve piston 30 is slideably mounted in a central sleeve 32 of the casing 26. The upper end of the casing 26 is closed by a cap 33, and between the cap 33 and the top of the piston 30 is a thrust spring 34 that urges the valve, 27 to closed position. The bottom wall 35 of the air chamber 23 includes passageways 36 and encircling the latter is an annular washer 37 of rubber or other flexible material designed to effect an air-tight joint during the sand blowing operation.

Slideably mounted on rollers 38 that are journaled on the inner sides of the side walls of the hood 24 is a plate 39 having an opening 40 therein which is adapted, in one position of the plate 39, to register with the lower end of the hopper 25 and in another position of the plate 39, to register with the bottom wall 35 of the air chamber 28. The plate 39 slideably engages the lower side of the washer ring 37 and also the lower edge of a sealing collar 41 that encircles the discharge end of the hopper. Secured to the under side of the plate is a depending tubular member 42 that forms a movable sand transfer member or carrier which, when in the position shown in Fig. 1, receives from the hopper 25, a charge of sand which is at least sufficient to make the core, and when in position below the air chamber 28 discharges a part of its load of sand under the pressure of an air blast into the underlying core-box. The bottom wall 43 of the sand carrier is formed as a grid, the openings 44 of which register with ducts 45 formed through the top member 46 of a divided core-box attached to the wall 43. The ducts 45 lead into a semi-cylindrical chamber 47 in the member 46, and this chamber is adapted for registration with a mating semi-cylindrical chamber 48 in the upper portion of the lower section 49 of the core-box. As is usual in core-boxes of this type that are filled by sand introduced under air-pressure, the walls of the lower section 49 of the core-box and the lower portion of the walls of the upper section of the core-box contain ducts 50 that are too fine to pass the sand but permit the escape of most of the air, these ducts 50, of course, being finer than the sand admission ducts 45.

The lower section 49 of the core-box rests on a platform 51 that, in turn, is mounted on and secured to, the top wall 52 of a cylinder 53. This cylinder 53 telescopes over a piston 54 that is mounted on the upper end of a piston rod 55, substantially the lower half of this rod 55 having a screw thread 56. The rod 55 is slideably mounted in a central sleeve 57 of a stationary cylinder 58 that is mounted on and attached to the top wall 22 of the base platform 23. Between the lower end of the cylinder 58 and the top wall 22 of the platform 23 is a flange 59 of a depending well 60, with which the lower end of the threaded portion 56 of the rod 55 slideably engages. The flange 59 is attached by cap, screws 61 to the lower end of the cylinder 58, and the latter and the flange 59 are both attached to the top plate 22 of the platform 23 by machine screws 62. Mounted on the threaded portion 56 of the rod 55 is a nut 63 carrying a worm wheel 64 engaged and driven by a worm 65 on a cross shaft 66, which may be turned by any suitable means such as a hand wheel (not shown). By turning the worm 65,the piston 54 may be raised or lowered relative to the cylinder 53., A pin 67 in the piston 54 extends through a hole in the top wall 68 of the stationary cylinder 58 to prevent the rotation of the piston 55 when the worm 65 is rotated to raise or lower the piston 55. The lower portion of the cylinder 58 is filled with oil as indicated in Fig. 1.

For shifting the sand carrier 42 back and forth between the sand hopper 25 and the air chamber 28, there is employed an air cylinder 69 that is pivotally mounted substantially mid-length thereof on a bracket 70 attached to the rear end of the hood 24. Within the cyilnder 69 is a piston 71, the rod 72 of which is pivotally connected at 73 to a depending web or flange 74 on the upper wall 75 of the sand carrier 42. The plate 39 is long enough to close the discharge opening 76 of the hopper 25 when the sand carrier 42 is shifted to the blowing position. The means for operating this sand carrier shifting mechanism will be described in connection with the control mechanism for the core-making machine.

Describing next the control mechanism of the apparatus, 77 designates a main air supply conduit leading from the source of compressed air and communicates through a port 78 with the valve chamber 31. An air volume control valve 79 for regulating the amount of air passing to the valve chamber 31 is located in the conduit 77. 80 designates a branch air conduit connected at its upper end to the conduit 77 and at its lower end to a tank 81 (Fig. 1) conveniently mounted on the base of the machine frame or on the floor beneath the cross connecting member 21, and suitably secured to the latter by hoops or straps 82. This tank 81 contains a supply of compressed air for operating the core-box lift previously described. A conveniently located valve 83 in the main air supply conduit 77 turns the air, usually at about 130 pounds pressure on and off the entire apparatus. If desired, a gauge 84 for indicating the pressure in the system and an automatic oiler 85 for lubricating the valves may be located in the conduits 77 and 80.

For the purpose of clarity, the portions of the control mechanism of the core-making machine which permit manual, automatic, and semi-automatic operation of the machine will be separately described.

Manual operation The control mechanism which permits manual control of the core-making machine is diagrammatically illustrated in Fig. 2. The control mechanism includes a series of two-way selector valves 86, 87, 88, 89, and which are connected between the source of pressure air and the operating mechanisms of the core-making machine and by-pass valves 91 and 92 which are connected with the selector valve 86 through the conduits 93 and 94. The selector valves 86-90 detachably interconnected for simultaneous operation by the links 95, 96, 97, 98, 99, 100, and 101 and the screws 102. For manual operation of the core-making machine, the selector valves 8690 are set in theposition shown in Fig. 2 which permits the pressure air to flow through the selector valves 86-90 in the manner indicated by the arrows in Fig. 2. In addition, for manual operation, the by-pass valve 91 is closed and the by-pass valve 92 opened.

Describing the air supply to the sand carrier shifting mechanism, the valve chamber 31interconnects with the selector valve 86 through the conduits 103, 104, 105, and 106. An air filter 107 may be inserted in the conduit for cleaning the air passing from the valve chamber 31 to the selector valve 86. The pressure air passes through the selector valve 86, conduit 94, by-pass valve 92, and conduit 108 to the three-position, two-way sand carrier refill valve 109. When the control lever 110 of the refill valve 109 is placed in the position shown in Fig. 2, the pressure air passes through the valve 109 in the manner indicated by the arrow from the conduit 108 to a conduit 111, and a conduit-112 is vented to the atmosphere through the refill valve and a speed control valve 113 on an exhaust port of the refill valve 109. By opening or closing the speed control valve 113, one can control the rate at which air can beexhausted from the conduit 112. From the conduit 111, the pressure air duit 115, selector valve 90, conduit 112, refill valve 109,

and speed control valve 113 to the atmosphere. This permits the air on the far side of the air cylinder 69 to leave the cylinder as the piston is forced rearwardly. When the control lever 110 for the sand carrier refill valve 109 is moved to the right hand dotted position shown in Fig. 2, pressure air passes from the conduit 108 through the refill valve 109 to the conduit 112, and thence through the selector valve 90, and conduit 115 to the far end of the air cylinder 69, and air from the inner end of the cylinder 69 escapes to the atmosphere through the conduit 114, selector valve 89, conduit 111, refill valve 109, and speed control valve 113 to the atmosphere, thereby shifting the sand carrier 42 into alignment with the air chamber 28. When the control handle 110 of the sand refill valve 109 is in the central dotted position shown in Fig. 2, there is no interconnection between the conduits 108, 111, and 112, or between the conduits 108, 111, 112 and the speed control valve 113, thus preventing any movement of the air cylinder 69 and the sand carrier 42.

An air operated vibrator 116 is attached to the hopper 25 for shaking the sand into the sand carrier 42. The vibrator 116 is connected to the valve chamber 31 through the conduit 104 and a vibrator valve 117. When the sand carrier 42 moves into alignment with the sand hopper 25, it depresses a piston 118 of the vibrator valve 117 which opens the valve and permits air pressure to pass from the valve chamber 31 to the air operated vibrator 116. The vibrator valve 117 which is similar in construction to various safety valves of the system is illustrated in Fig. 6. The vibrator valve 117 includes a disc 119 which is biased by a thrust spring 120 against a valve seat 121. The piston 118 connects with the face of the disc and extends outwardly of the body of the valve 117. When the piston 118 is depressed, it forces the disc 119 from the valve seat 120 against the force of the spring 120, thereby opening the vibrator valve 117.

Describing next the control mechanism for operating the core-box clamping mechanism, pressure air in the conduit 106 passes through the selector valve 86 and conduits 94 and 122, to a safety valve 123 which may be similar in construction tothe vibrator valve 117. The safety valve 123 is positioned so that when the sand carrier 42 moves into registration with the air chamber 28, the piston 124 will be depressed opening the safety valve 123. Pressure air passing through the safety valve 123 moves through the conduit 125 to a manually operable clamp valve 126 which may have an internal construction similar to the vibrator valve 117. When a pivoted lever 127 on the valve is depressed, pressure air passes from the conduit 125 through the valve 126 to a conduit 128 and thence to the upper end of a double valve 129. The double valve 129 includes the control levers 130 and 131 which are normally retained in the positions shown in Fig. 2 by the return springs 132. The upper control lever 130 must be moved towards the dotted position shown in Fig. 2 before the lower control lever 131 can be moved. As will be seen, this prevents the operator from operating the blowing mechanism of the core-making machine before the core-box sections 46 and 49 and sand carrier 42 are firmly clamped against the air chamber 28. When the control lever 130 is in the position shown in Fig. 2, the conduit 128 is closed and a conduit 133 is connected to an exhaust port 134 on the double valve 129. When the control lever 130 is moved to the dotted position shown in Fig. 2, pressure air passes from the conduit 128 through the double valve 129 to the conduit 133,,and thence to the selector valve 87. Thus, when the sand carrier 42 is in its forwardmost position in alignment with the air chamber 28 and the operator depresses the control lever 127 with one hand, and moves the control lever to the dotted position of Fig. 2 with his other hand, pressure air can flow from the valve chamber 31 to the selector valve 87, and thence through a branched conduit 135 to a diaphragm valve 136 and exhaust valve 137. By requiring the manipulation of the two control levers 127 and 130 for operating the clamping mechanism, the operator is required to use both hands which removes the danger of the operator placing his hands between the core-box sections 46 and 49 while clamping.

The diaphragm valve 136 may be mounted on one of the side frames 20 and is supplied with pressure from the tank 81 by means of a conduit 138. The diaphragm valve 136 which is shown in Fig. 5, includes a short pipe section 139, the bore of which is bridged at 140. It has radial ports 141 on opposite sides of the bridge 140. A part of the bridged and ported portion of the pipe section 139 is encircled by an annular chambered valve 142 that is pressed to the position shown in Fig. 5 by a spring 143, and is moved in the reverse direction by air pressure in the chamber 144 acting through a diaphragm 145 and a pair of rods 146 connecting the diaphragm 145 to the valve 142. When pressure in the chamber 144 forces the diaphragm 145 rearward, the valve 142 is moved rearward so as to encircle the ported portion of the pipe section 139, thereby permitting pressure air to flow from the tank 81 through the conduit 138, a curved duct 147, the pipe section 139, by-passing the bridge 140 by flowing through the ports 141 to a conduit 148. The conduit 148 connects with a needle valve 149 for controlling the pressure air to the clamping cylinder 53. The pressure air passes from the needle valve 149 through a branched conduit 150 to the top of the exhaust valve 137 and thence to the cylinder 53.

The exhaust valve 137 for the clamping cylinder, illustrated in Fig. 7, includes a piston 151 having a domeshaped head 152 which is adapted for engagement with the valve seat 153. The piston is slideably mounted within a cylindrical casing 154 of the valve. Radial passageways 155 extend through the upper portion of the casing 154 for permitting air to exhaust from the upper portion of the casing 154. When pressure air passes through the conduit 135 to the lower end of the exhaust valve 137, the piston 151 is forced upward so as to engage the valve seat 153, thereby closing off the interior of the valve from the conduit 150 which connects with the clamping cylinder 53. When the pressure in the conduit 150 is greater than the pressure in the conduit 135, the piston 151 is forced downwardly thereby :opening the exhaust valve 137 and permitting the air in the clamping cylinder 53 to exhaust through the passageways 155 of the exhaust valve 137.

Thus, when the clamp control lever 130 is moved to the dotted position of Fig. 2, pressure air passes through the selector valve 87 and conduit 135 to the diaphragm valve 136. This causes the valve 136 to operate permitting air to flow from the tank 81 through the conduits 138 and 148, needle valve 149, and conduit 150 to the clamping cylinder 53. Simultaneously, air passes through the conduit 135 to the exhaust valve 137 closing the exhaust valve 137. The pressure passing through the passageway 150 to the clamping cylinder 53 causes the latter to rise, thereby closing the core-box sections 47 and 48 and forcing the sand carrier 42 hard against the ring washer 37 making an air-tight joint. When the clamp control lever 130 is released, the lever 130 moves back to its original position causing the diaphragm valve 136 to close. The conduit 135, selector valve 87, and conduit 133 are exhausted to the atmosphere through the exhaust port 134 in the double valve 129. The reduced pressure flowing to the diaphragm 145 of the diaphragm valve 136 causes the valve 136 to close, thereby closing the conduit 138 leading from the air tank 81 and connecting the conduit 148 to the atmosphere through an exhaust port 156 of the diaphragm valve 136. At the same time, the decrease in pressure in the lower portion of the exhaust valve 137 causes the exhaust valve 137 to open, thereby permitting the clamping cylinder53 and conduit 150 to exhaust to the atmosphere.

Referring next to the sand blowing portion of the system, 157 designates a conduit which connects the upper end of the casing 26 of the blow valve 27 with a diaphragm valve 158 illustrated in Fig. 9. The diaphragm valve 158 has a pipe section 159, the bore of which is bridged at 160 and has radial ports 161 on opposite sides of the bridge 160. This bridged and ported portion of the pipe section 159 is encircled by an annular chambered valve 162 that is pressed to the position shown in Fig. 9 by a spring 163, and is moved in the reverse direction by air pressure in a chamber 164 acting through a diaphragm 165 and rods 166. With the parts in the position shown in Fig. 9, pressure air from the valve chamber 31 is able to flow through the conduits 1413 and 184, the pipe section 159, bypassing the bridge 168 by flowing through the ports 161, the chamber of the valve 162, and the ports 161, and thence through the curved duct 168 and the conduit 157 into the space above the valve piston of the blow valve 27. The air pressure above the piston 30 balances the pressure below the piston 30, and the force of the spring 34 against the piston 30 is then sufficient to keep the blow valve 27 closed. When pressure air enters the diaphragm chamber 164, through a conduit 169, the diaphragm 165 and rods 166 force the valve 162 rea.- ward closing off the conduit 184 and allowing pressure air to exhaust to the atmosphere from the space above the valve piston 38 through the conduit 157, duct 168, ports 161, and exhaust port 170. The pressure within the valve chamber 30 is then sufiicient to lift the piston 30 against the force of the spring 34, allowing pressure air to pass from the valve chamber 30 into the air chamber 28.

The passageway 122, which is in communication with the source of pressure air, connects with a safety valve 171. The safety valve 171 is positioned so that when the clamping cylinder 53 is at its uppermost position, that is, when the core-box sections 46 and 49 are closed and the sand carrier 42 forced against the ring washer 37, the platform 51 depresses the piston 172 of the safety valve 171 thereby opening the valve. Pressure air passing through the safety valve 171 continues through a conduit 173 to the lower or flow control portion of the double valve 129.

The blow control portion of the double valve 129 is controlled by the control lever 131 which is normally retained in closed position by the associated spring 132. When the blow control lever 131 is pulled forwardly to the dotted position shown in Fig. 2, pressure air can pass from the conduit 173 through the blow control portion of the double valve 129, a conduit 174, the selector valve 88, and a branched conduit 169 to the diaphragm valve 158 and an exhaust valve 175.

The exhaust valve 175, shown in Fig. 8, includes a housing 176 which is proportioned so as to form a cylinder 177 and a valve chamber 178. A conduit 179 connects the air chamber 28 with the valve chamber 178 and the conduit 169 connects the selector valve 88 and diaphragm chamber 164 of the diaphragm valve 158 with the cylinder 177. A piston 180, the outer end of which engages the lower end of a pivoted lever 181, slides within the cylinder 177. The lever 181 is pivoted on a bracket 182 on the housing 176 by a pin 183 and has a head 184 which engages the upper wall 185 of the valve housing 176 so as to seal. a passageway 186 leading to the valve chamber 178. A spring 187 connected between the housing 176 and the lever 181 biases the lever 181 so that the lower portion of the lever engages the piston 180. When pressure air is transmitted to the cylinder'177 fromthe conduit .169, the piston 180 is forced outwardly of the cylinder 177; The outward movement of the piston 180 causes the lever 181 to rotate about the pin 183 causing the lever head 184 to seat on the upper wall 185 of the valve housing 176 thereby sealing the valve chamber 178 from the atmosphere. When the pressure in the cylinder 177 is subsequently reduced, the spring 187 rotates the lever 181 forcing the piston 180 inwardly of the cylinder 177 and raising the lever head 184 from the wall 185 thereby opening the valve chamber 178 to the atmosphere. Thus, when pressure is transmitted to the cylinder 177 through the conduit 169, the air chamber 28 is sealed from the atmosphere and when the pressure in the conduit 169 and cylinder 177 is reduced, the air chamber 28 is exhausted to the atmosphere through the exhaust valve 175.

When the blow control lever 131 of the double valve 129 is held in the dotted position of Fig. 2, pressure air is transmitted to the diaphragm 165 actuating the diaphragm valve 158 so as to permit pressure air to pass from the valve chamber 31 through the air chamber 28 into the sand carrier 42 forcing sand into the core-box. During this blowing period, the pressure within the con duit 169 keeps the exhaust valve 175 in closed position. When the blow control lever 131 is released, the blow valve portion of the double valve 1.29 is closed. The exhaust 134 of the double valve 129 is then connected to the conduit 174, the selector valve 88, and conduit 169. The reduced pressure in the conduit 169 causes the exhaust valve 175 to open thereby venting the air chamber 28 to the atmosphere. The reduced pressure against the diaphragm 165 of the diaphragm valve 158 causes pressure air to be transmitted to the upper end of the blow valve piston 30 thereby closing the blow valve 27.

To manually operate the core-making machine so as to make a core, an operator performs the following sequence of operations. The operator first moves the control lever of the sand carrier refill valve 109 to the position shown in Fig. 2. This causes the sand box to move into alignment with the hopper. When the sand carrier is beneath the hopper, the vibrator valve 117 is actuated, which permits air to pass to the air vibrator 116 on the hopper 25 which shakes the sand within the hopper 25 causing it to move into the sand carrier 42. After a short interval, during which time the sand flows into the sand carrier 42, the control lever 110 of the sand carrier refill valve 109' is moved to the forward position shown in dotted outline in Fig. 2. This causes the sand carrier 42 to move forwardly into alignment with the air chamber 28 and actuates the safety valve 123. The operator then depresses the lever 127 of the clamp safety valve 126 with one hand and moves the clamp control lever of the double valve 129 to the position shown in dotted outline in Fig. 2 with his other hand. This permits air to pass to the clamping cylinder 53 causing the core-box sections 46 and 49 to be clamped together and the sand carrier 42 to be clamped against the air chamber 28. After the core-box is in clamped position, the operator releases his hand from the lever 127 controlling the clamp safety valve 126 and moves the blow control lever 131 of the double valve 129 to the position shown in dotted outline in Fig. 2. This causes the blow valve 27 to open permitting air to blow sand from the sand carrier 42 into the core-box. When the core-box is completely filled with sand, the operator releases the blow control lever 131 causing the blow valve 27 to close and the air chamber 28 to exhaust through the exhaust valve 175. The operator then releases the clamp control lever 130 which releases the air pressure to the clamp cylinder 53 permitting the platform to lower thereby separating the core-box sections 46 and 49.

The safety valves 123 and 171, associated with the control mechanism, prevent the core-making machine mechanisms from operating out of proper sequence. This control the rate at which air can be exhausted from the conduit 112. From the conduit 111, the pressure air passes through the selector valve 89 and a conduit 114 to the inner end of the air cylinder 69 which causes the piston 71 to move rearwardly, thereby shifting the sand carrier into alignment with the sand hopper 25. The outer end of the cylinder 69 is connected through a conduit 115, selector valve 90, conduit 112, refill valve 109, and speed control valve 113 to the atmosphere. This permits the air on the far side of the air cylinder 69 to leave the cylinder as the piston is forced rearwardly. When the control lever 110 for the sand carrier refill valve 109 is moved to the right hand dotted position shown in Fig. 2, pressure air passes from the conduit 108 through the refill valve 109 to the conduit 112, and thence through the selector valve 90, and conduit 115 to the far end of the air cylinder 69, and air from the inner end of the cylinder 69 escapes to the atmosphere through the conduit 114, selector valve 89, conduit 111, refill valve 109, and speed control valve 113 to the atmosphere, thereby shifting the sand carrier 42 into alignment with the air chamber 28. When the control handle 110 of the sand refill valve 109 is in the central dotted position shown in Fig. 2, there is no interconnection between the conduits 108, 111, and 112, or between the conduits 108, 111, 112 and the speed control valve 113, thus preventing any movement of the air cylinder 69 and the sand carrier 42.

An air operated vibrator 116 is attached to the hopper 25 for shaking the sand into the sand carrier 42. The vibrator 116 is connected to the valve chamber 31 through the conduit 104 and a vibrator valve 117. When the sand carrier 42 moves into alignment with the sand hopper 25, it depresses a piston 118 of the vibrator valve 117 which opens the valve and permits air pressure to pass from the valve chamber 31 to the air operated vibrator 116. The vibrator valve 117 which is similar in construction to various safety valves of the system is illustrated in Fig. 6. The vibrator valve 117 includes a disc 119 which is biased by a thrust spring 120 against a valve seat 121. The piston 118 connects with the face of the disc and extends outwardly of the body of the valve 117. When the piston 118 is depressed, it forces the disc 119 from the valve seat 120 against the force of the spring 120, thereby opening the vibrator valve 117.

Describing next the control mechanism for operating the core-box clamping mechanism, pressure air in the conduit 106 passes through the selector valve 86 and conduits 94 and 122, to a safety valve 123 which may be similar in construction to the vibrator valve 117. The safety valve 123 is positioned so that when the sand carrier 42 moves into registration with the air chamber 28, the piston 124 will be depressed opening the safety valve 123. Pressure air passing through the safety valve 123 moves through the conduit 125 to a manually operable clamp valve 126 which may have an internal construction similar to the vibrator valve 117. When a pivoted lever 127 on the valve is depressed, pressure air passes from the conduit 125 through the valve 126 to a conduit 128 and thence to the upper end of a double valve 129. The double valve 129 includes the control levers 130 and 131 which are normally retained in the positions shown in Fig. 2 by the return springs 132. The upper control lever 130 must be moved towards the dotted position shown in Fig. 2 before the lower control lever 131 can be moved. As Will be seen, this prevents the operator from operating the blowing mechanism of the core-making machine before the core-box sections 46 and 49 and sand carrier 42 are firmly clamped against the air chamber 28. When the control lever 130 is in the position shown in Fig. 2, the conduit 128 is closed and a conduit 133 is connected to an exhaust port 134 on the double valve 129. When the control lever 130 is moved to the dotted position shown in Fig. 2, pressure air passes from the conduit 128 through the double valve 129 to the conduit 133, and thence to the selector valve 87. Thus, when the sand carrier 42 is in its forwardmost position in alignment with the air chamber 28 and the operator depresses the control lever 127 with one hand, and moves the control lever to the dotted position of Fig. 2 with his other hand, pressure air can flow from the valve chamber 31 to the selector valve 87, and thence through a branched conduit 135 to a diaphragm valve 136 and exhaust valve 137. By requiring the manipulation of the two control levers 127 and 130 for operating the clamping mechanism, the operator is required to use both bands which removes the danger of the operator placing his hands between the core-box sections 46 and 49 while clamping.

The diaphragm valve 136 may be mounted on one of the side frames 20 and is supplied with pressure from the tank 81 by means of a conduit 138. The diaphragm valve 136 which is shown in Fig. 5, includes a short pipe section 139, the bore of Which is bridged at 140. It has radial ports 141 on opposite sides of the bridge 140. A part of the bridged and ported portion of the pipe section 139 is encircled by an annular chambered valve 142 that is pressed to the position shown in Fig. 5 by a spring 143, and is moved in the reverse direction by air pressure in the chamber 144 acting through a diaphragm 145 and a pair of rods 146 connecting the diaphragm 145 to the valve 142. When pressure in the chamber 144 forces the diaphragm 145 rearward, the valve 142 is moved rearward so as to encircle the ported portion of the pipe section 139, thereby permitting pressure air to flow from the tank 81 through the conduit 138, a curved duct 147, the pipe section 139, bypassing the bridge 140 by flowing through the ports 141 to a conduit 148. The conduit 148 connects with a needle valve 149 for controlling the pressure air to the clamping cylinder 53. The pressure air passes from the needle valve 149 through a branched conduit 150 to the top of the exhaust valve 137 and thence to the cylinder 53.

The exhaust valve 137 for the clamping cylinder, illustrated in Fig. 7, includes a piston 151 having a domeshaped head 152 which is adapted for engagement with the valve seat 153. The piston is slideably mounted within a cylindrical casing 154 of the valve. Radial passageways 155 extend through the upper portion of the casing 154 for permitting air to exhaust from the upper portion of the casing 154. When pressure air passes thnough the conduit 135 to the lower end of the exhaust valve 137, the piston 151 is forced upward so as to engage the valve seat 153, thereby closing ofi the interior of the valve from the conduit 150 which connects with the clamping cylinder 53. When the pressure in the conduit 150 is greater than the pressure in the conduit 135, the piston 151 is forced downwardly thereby opening the exhaust valve 137 and permitting the air in the clamping cylinder 53 to exhaust through the passageways 155 of the exhaust valve 137.

Thus, when the clamp control lever 130 is moved to the dotted position of Fig. 2, pressure air passes through the selector valve 87 and conduit 135 to the diaphragm valve 136. This causes the valve 136 to operate permitting air to flow from the tank 81 through the conduits 138 and 148, needle valve 149, and conduit 150 to the clamping cylinder 53. Simultaneously, air passes through the conduit 135 to the exhaust valve 137 closing the exhaust valve 137. The pressure passing through the passageway 150 to the clamping cylinder 53 causes the latter to rise, thereby closing the core-box sections 47 and 48 and forcing the sand carrier 42 hard against the ring washer 37 making an air-tight joint. When the clamp control lever 130 is released, the lever 130 moves back to its original position causing the diaphragm valve 136 to close. The conduit 135, selector valve 87, and conduit 133 are exhausted to the atmosphere through the exhaust port 134 in the double valve 129. The reduced pressure flowing to the diaphragm 145 of the diaphragm valve 136 causes the valve 136 to close, thereby closing the conduit 138 leading from the air tank 81 and connecting the conduit 148 to the atmosphere through an exhaust port 156 of the diaphragm valve-136. At the same time, the decrease in pressure in-the lower portion of the exhaust valve 137 causes the exhaust valve 137 to open, thereby permitting the clamping cylinder-53 and conduit 150 to exhaust to the atmosphere.-

Referring next to the sand blowing portion of the system, 157 designatesa conduit which connects the upper end of the casing 26- of the blow valve 27 with a diaphragm valve 158 illustrated in Fig. 9. The diaphragm valve 158 has a pipe section 159, the bore of which is bridgedat 160and has radial ports 161 on opposite sides of the bridge 160. This bridged and ported portion of the pipe section-159'is encircled by an annular chambered valve 162 that is pressed to, the position shown in Fig. 9 by a spring 163, and is moved'in the reverse direction by air pressure in a chamber 164 acting through a diaphragm 165 and rods 166- With the parts in the position shown in, Fig. 9, pressure air'from the valve chamber 31 is able to fiow through the conduits 103 and 104, the pipe section 159, by-passing the bridge 160 by flowing through the ports 161, the chamber of the valve 162, and the ports 161, and thence through the curved duct 168 and the conduit 157 into the space above the valve piston of the blow valve 27. The air ressure above the piston 30 balances the pressure below the piston 30, and the force of the spring 34 against the piston 30 is then sufiicient to keep the blow valve 27 closed. When pressure air enters the diaphragm chamber 164, through a conduit 169, the diaphragm 165 and rods 166 force the valve 162 rearward closing olf the conduit 104 and allowing pressure air to exhaust to the atmosphere from the space above the valve piston 30 through the conduit 157, duct 168, ports 161, and exhaust port 170. The pressure within the valve chamber 30 is then suflicient to lift the piston 30 against the force of the spring 34, allowing pressure air to pass from the valve chamber 30 into the air chamber 28.

The passageway 122, which is in communication with the source of pressure air, connects with a safety valve 171. The safety valve 171 is positioned so that when the clamping cylinder 53 is at its uppermost position, that is, when the core-box-sections 46 and 49 are closed and the sand carrier 42 forced against the ring washer 37, the platform 51 depresses the piston 172 of the safety valve 171 thereby opening the valve. Pressure air passing through the safety valve 171 continues through a conduit 173 to the lower or flow control portion of the double valve 129.

The blow control portion of the double valve 129 is controlled by the control lever 131 which is normally retained in closed position by the associated spring 132. When the blow control lever 131 is pulled forwardly to the dotted positionshown in Fig. 2, pressure air can pass from the conduit 173 through the blow control portion of the double valve 129, a conduit 174, the selector valve 88, and a branched conduit 169 to the diaphragm valve 158 and an exhaust valve 175.

The exhaust valve 175, shown in Fig. 8, includes a housing 176 which is proportioned so as to form a cylinder 177 and a valve chamber 178. A conduit 179 connects the air chamber 28 with the valve chamber 178 and the conduit 169 connects the selector valve 38 diaphragm chamber 164 of the diaphragm valve 15% with the cylinder 177. A piston 180, the outer end of which engages the lower end of a pivoted lever 181, slides within the cylinder 177. The lever 181 is pivoted on a bracket 182 on the housing 176 by a pin 183 and has a head 134 which engages the upper wall 185 of the valve housing 176 so as to seal a passageway 186 leading to the valve chamber 178. A spring 187 connected between the housing 176 and the lever 181 biases the lever 181 so that the lower portion of the lever engages the piston 180; When pressure air is transmitted to the cylinder-177 =fromthe conduit-169; the piston-180 is forcedoutwardly of the cylinder 177; The outward movement of the piston 180 causes the lever lfilto rotate about the pin 183 causing the lever head 184 to seat on the upper wall 185 of the valve housing 176 thereby sealing the valve chamber 178 from the atmosphere. When the pressure in the cylinder 177 is subsequently reduced, the spring 187 rotates the lever 131 forcing the piston 180 inwardly of the cylinder 177 and raising the lever head 184 from the wall 185 thereby opening thevalve chamber 178 to the atmosphere. Thus, when pressure is transmitted to the cylinder 177 through the conduit 169, the air chamber 28 is sealed from the atmosphere and when the pressure in the conduit 169 and cylinder 177 is reduced, the air chamber 28 is exhausted to the atmosphere through the exhaust valve 175.

When the blow control lever 131 of the double valve 129 is held in the dotted position of Fig. 2, pressure airis transmitted to the diaphragm 165 actuating the diaphragm valve 158 so as to permit pressure air to pass from the valve chamber 31 through the air chamber 28 into the sand carrier 42 forcing sand into the core-box. During this blowing period, the pressure within the conduit 169 keeps the exhaust valve 175 in closed position. When the blow control lever 131 is released, the blow valve portion of the double valve 129 is closed. The exhaust 134 of the double valve 129 is then connected to the conduit 174, the selector valve 83, and conduit 169. The reduced pressure in the conduit 169 causes the exhaust valve 175 to open thereby venting the air chamber 28 to the atmosphere. The reduced pressure against the diaphragm 165 of the diaphragm valve 158 causes pressure air to be transmitted to the upper end of the blow valve piston 30 thereby closing the blow valve 27.

To manually operate the core-making machine so as to make a core, an operator performs the following sequence of operations. The operator first moves the control lever of the sand carrier refill valve 199 to the position shown in Fig. 2. This causes the sand box to move into alignment with the hopper. When the sand carrier is beneath the hopper, the vibrator valve 117 is actuated, which permits air to pass to the air vibrator 116 on the hopper 25 which shakes the. sand within the hopper 25 causing it to move into the sand carrier 42. After a short interval, during which time the sand flows into the sand carrier 42, the control lever 110 of the sand carrier refill valve 109 is moved to the forward position shown in dotted outline in Fig. 2. This causes the sand carrier 42 to move forwardly into alignment with the air chamber 28 and actuates the safety valve 123. The operator then depresses the lever 127 of the clamp safety valve 126 with one hand and moves the clamp control lever of the double valve 129 to the position shown in dotted outline in Fig. 2 with his other hand. This permits air to pass to the clamping cylinder 53 causing the core-box sections 46 and 49 to be clamped together and the sand carrier 42 to be clamped against the air chamber 28. After the core-box is in clamped position, the operator releases his hand from the lever 127 controlling the clamp safety valve 126 and moves the blow control lever 131 of the double valve 129 to the position shown in dotted outline in Fig. 2. This causes the blow valve 27 to open permitting air to blow sand from the sand carrier 42 into the core-box. When the core-box is completely filled with sand, the operator releases the blow control lever 131 causing the blow valve 27 to close and the air chamber 23 to exhaust through the exhaust valve 175. The operator then releases the clamp control lever 130 which releases the air pressure to the clamp cylinder 53 permitting the platform to lower thereby separating the core-box sections 46 and 49.

The safety valves 123 and 171, associated with the control mechanism, prevent the core-making machine mechanisms from operating out of proper sequence. This prevents damage toflthe machine and permits the operator to make perfect cores with ease.

Automatic operation For automatic operation of the core-making machine, the bypass valves 91 and 92 are closed and the selector valves 86-90 are adjusted to the position shown in Fig. 3. The adjustment of the selector valves 86-90 may be simply accomplished by moving the connecting link 100 to the right. When the selector valves 86-90 are set, as

shown in Fig. 3, gas can flow through the valves in the manner indicated by the arrows.

Describing the air supply to the sand carrier shifting mechanism, air passes from the valve chamber 31 through the conduits 103, 104, 105, 106, selector valve 86, and conduits 188 and 189 to a solenoid valve 190. .When the solenoid valve 190 is actuated, the air supply passes through the solenoid valve 190, conduit 191, selector valve 89, and conduit 114 to the inner end of the air cylinder 69 forcing the piston 71 of the cylinder 69 rearwardly thereby moving the sand carrier into engagement with the sand hopper 25. The air at the rearward end of the cylinder 69 escapes to the atmosphere through the conduit 115, selector valve 90, and through an exhaust port 192 in a solenoid valve 193. When the solenoid valve 190 is closed and the solenoid valve 193 opened, the air in the conduit 188 passes through the conduit 194, solenoid valve 193, selector valve 90, and conduit 115 to the rearward end of the air cylinder 69, and the air at the inner end of the cylinder 69 escapes to the atmosphere through the conduit 114, selector valve 89, conduit 191, and exhaust port 195 in the solenoid valve 190, thereby moving the sand carrier 42 into alignment with the air chamber 28.

When the sand carrier 42 moves into alignment with the sand hopper 25, the vibrator valve 117 is actuated permitting air to pass through the conduits 103 and 104 and the vibrator valve 117 to the air vibrator 116 on the sand hopper 25 thereby shaking the sand downwardly into the sand carrier 42.

A solenoid valve 196 controls the operation of the core-box lifting mechanism. When the solenoid valve 196 opens, air passes from the conduit 188 through a conduit 197, the solenoid valve 196, the conduit 198, selector valve 87, and the conduit 135 to the diaphragm valve 136 and exhaust valve 137 for the clamping cylinder 53. This causes the diaphragm valve 136 to open permitting air to flow from the tank 81 to the clamping cylinder 53 which causes the core-box sections 46 and 49 and sand carrier 42 to be clamped against the air chamber 28. When the solenoid valve 196 is closed, the conduits 198 and 135 are exhausted to the atmosphere through the exhaust port 199 in the solenoid valve 196. The reduced pressure in the conduit 135 causes the diaphragm valve to close and the exhaust valve 137 to open thereby releasing the pressure air in the conduits 148 and .150 and clamping cylinder 53. This causes the clamping cylinder 53 to lower thereby separating the core-box sections 46 and 49.

The operation of a solenoid valve 200 which is connected to the conduit 188 through conduit 201 contnols .the operation of the blowing mechanism. When the solenoid valve 200 is opened, air passes from the conduit 201; through the valve 200, conduit 202, selector valve 88, and branched conduit 169 to the diaphragm valve 158 and to the cylinder 177 of the exhaust valve 175, thereby operating the diaphragm valve 158 and closing the exhaust valve 175. The operation of the diaphragm valve 158 causes the blow valve 27 to open in the manner previously described thereby permitting air to flow from the valve chamber 31 through the air chamber 28 to the sand carrier 42 thereby forcing sand into the corebox sections 46 and 49. When the solenoid valve 200 is closed, the conduits 169 and 202 are exhausted to the atmosphere through the exhaust port 203 of the solenoid '10 valve 200. This causes the blow'valve 27 to close and the exhaust valve to open. The opening of the exhaust valve 175 permits the residual air within the air chamber 28 to escape before the clamping cylinder 53 moves downwardly.

An electrical circuit for operating the solenoid valves 190, 193, 196 and 200 is diagrammatically illustrated in Fig. 10. This circuit is designed so as to automatically control the operation of the solenoid valves 190, 193, 196 and 200 in sequence, so as to cause the various mechanisms of the core-making machine to perform a complete cycle of operation in the manufacture of a core. The cycle is normally started when the sand carrier 42 is in its forward position in alignment with the air chamber 28. When the sand carrier 42 is in its forward position, a switch 204 is closed. The electrical circuit includes a line switch 205 which connects the circuit to a source of power 206, a selector switch 207 which is used for setting the circuit to either automatic or semiautomatic operation, and the cycle start buttons 208 and 209 which are adapted for initiating the operation of the circuit. A fuse 210 in the circuit cuts off the current passing from the line switch 205 to the circuit in case of a short circuit in the system, or in case there is an excessive surge of current from the power source 206. Toset the electric circuit for automatic operation, the line switch 205 is closed and the selector switch 207 is set to the position shown in Fig. 10. Then, if the sand carrier 42 is in its forward position, the operator may initiate the operating cycle of the circuit by depressing the cycle start buttons 208 and 209. The start buttons 208 and 209 are spaced apart on the core-making machine so as to require the use of both hands of the operator for the initiation of the cycle. This removes the danger of the operator placing his hands between the core-box sections 46 and 49 during the clamping operation.

Closing the line switch 205 and depressing the cycle start buttons 208 and 209 permits the current to flow through conductors 210. and 211, a normally closed contact 212 of a relay 231, and conductor 213, to the solenoid 214 causing the solenoid valve 196 to open. The solenoid valve 196 controls the operation of the corebox lift mechanism in the manner previously described, clamping the core-box sections 46 and 49 together and clamping sand carrier 42 against the air chamber 28. When the core-box lift mechanism'moves to its upper position, a switch 215 closes permitting the current in the conductor 211 to flow through conductors 216 and 217 to a time delay unit 218. The time delay unit 218 may operate in any convenient manner, for example, current passing through a solenoid 219 might force a piston 220 in the time delay unit upwards against the force of a spring 221. The upper end of the piston 220 may slide within a dash pot 222 and the movement of the piston 220 may be controlled by regulating an orifice 223 in the dash pot 222. A switch 224 closeswhen the piston 220 of the time delay unit 218 begins its upward movement permitting current to flow from the conductor 217 through a conductor 225, switch 224, conductors 226 and 211, switch 212, and conductor 213 to the solenoid 214 thereby by-passing the start buttons 208 and 209. This allows the operator to release the start buttons 208 and 209 without interrupting the cycle of operation.

When the time delay unit 218 times out, that is, when the piston 220 moves to the end of its stroke, a switch 227 closes permitting current to flow from the conductor 217 through the switch 227, conductors 228 and 229, a .closed contact 230 of the relay 231, and a conductor 232 to the solenoid 233 which operates the solenoid valve 200 thereby initiating the blowing operation. When the switch 227 closes, current also passes from the conductor 217 through the switch 227 and conductor 228 to a second time delay unit 234. When the time delay unit 234 times out, a contact 235 in a switch 236 closes allowing current to pass from the conductor210 through a conductor 237,

contact 235, and conductor 238, to a solenoid 239 which controls the operation of the relay 231 causing an opening of the contacts 212 and 230 and closing of contacts 240 and 241. When the contacts 212 and 230 open, current can no longer fiow to the solenoids 214 and 233 causing the solenoid valves 196 and 200 to close. This stops the blowing operation and causes the lift cylinder 53 to move to the bottom of its stroke, thereby opening the two halves 46 and 49 of the core-box. As soon as the lift cylinder starts downward, the switch 215 opens causing the time delay units 218 and 234 to reset themselves.

When the COI'fi-tbOX lift cylinder 53 moves to the bottom of its stroke, a switch 242 closes permitting current to fiow from the conductor 210 through the switch 242, conductor 243 and contact 240 to the solenoid 244 thereby operating the solenoid valve 190 which controls the rearward movement of the sand carrier mechanism causing the sand carrier 42 to move into alignment with the sand hopper 25. When the sand carrier 42 is not in its rearward position, a contact 245 on a double switch 246 is closed allowing the current to flow from the conductor 210 through the contact 245, conductor 247, contact 241, and the selector switch 207 and conductor 238 to the solenoid 239 thereby retaining the relay 231 energized.

When the sand carrier 42 reaches its rearward position, it operates the double switch 246, opening the contact 245 thereby preventing current from flowing to the relay 2'31 which causes the contacts 212 and 230 to close and contacts 240 and 241 to open. A contact 248 on the double switch 246 also closes permitting current to flow through a conductor 249 to the time delay unit 250. The operation of the relay opens contact 240 which shuts off the current to the solenoid 244 thereby closing the solenoid valve 190. As soon as the time delay unit 250 begins to operate, an instantaneous contact 251 closes, permitting current to flow from the conductor 210 through a conductor 237, a contact 257 in switch 236, a conductor 252, and contact 251 to the time delay unit 250 thereby keeping this unit energized.

When time delay unit 250 times out, a contact 253 closes allowing current to flow from the conductor 237 through a conductor 254 to a solenoid 2 55 of the solenoid valve 193 which controls the forward movement of the sand carrier 42 so as to bring the carrier 42 into alignment with the air chamber 28. As the sand carrier 42 moves to its forward position, the double switch 246 resets itself and the time delay unit 250 is then energized as set forth above by current flowing through the contacts 236 and 251 and the conductors 237 and 252. When the sand carrier 42 reaches its forward position, the circuit is in position to reactuate the cycle when the start buttons 208 and 209 are again depressed by the operator.

An emergency stop button 256 is provided in the conductor 210 for stopping the sand carrier 42 at any point. When the emergency stop button 256 is depressed, current can no longer flow from the power source 206 to the conductor 210. The operation of the circuit is therefore immediately stopped and the operating mechanisms of the core-marking machine held in position until the stop button 256 is released. As soon as the stop button 256 is released, the sand carrier 42 will continue in the direction it has been going and complete the operating cycle. The switches 204, 215, 242, and 246 in the circuit prevent the various elements of the circuit from operating out of sequence.

In summary, the operator may set the control mechanism of the core-making machine for automatic operation when the sand carrier is in its forward position by setting the selector valves 8690 to automatic position, as shown in Fig. 3, closing the by-pass valves 91 and 92, closing the line switch 205, and setting the selector switch 207 to automatic position as illustrated in Fig. 10. The operator may then in'tiate the operating cycle by simultaneously pressing both star-t buttons 208 and 209 and holding these buttons depressed until the sand carrier 42 is sealed against the air chamber 28. The operator may then release the start buttons 208 and 209 without distunbing the sequence of operations of the core-making machine.

Semi-automatic operation Where more than one core can be blown by a single load of the .sand carrier 42, the operator may set the core-making machine for semi automatic operation wherein the core-making machine may be operated automatically except for the loading of the sand carrier 42 which is accomplished manually by means of the sand box refill valve 109. The air line and valve system may be set for semi automatic operation of the core-making machine by opening the by-pass valve 91, closing bypass valve 92, and placing the selector valves 86-90 in the position shown in Fig. 4. To position the selector valves 86-90, the operator removes the screws 102 connecting the links 98 and 99 with the link 100 and then moves the link 100 to the right and the connecting link 101 to the left. The electrical control means is set for semi-automatic operation by closing the line switch 205 and moving the selector switch 207 to open position (shown in dotted outline in Fig. 10).

To operate the sand carrier moving mechanism, the operator manipulates the sand carrier refill valve 109 in the manner described in the discussion of the manual operation of the core-making machine. When the valve lever is in the position shown in Fig. 4, pressure air can flow from the valve chamber 28 through the conduits 103 and 104, air filter 107, conduits 105, 106 and 93, bypass valve 91, and conduit 108 to the sand carrier refill valve 109. The air passes through the valve 109, conduit 11 1, selector valve 89, and conduit 114, to the inner end of the air cylinder 69. Simultaneously, air is vented from the rear end of the air cylinder 69 through the conduit 1'15, selector valve '90, conduit 112, refill valve 109, and speed control valve 1003. To move the sand carrier 42 to its forward position in alignment with the air chamber 28, the refill valve lever 110 is moved to the dotted position shown in Fig. 4 which causes air pressure to be sent to the rearward end of the air cylinder 69 and allows the air :to escape from the forward end of the cylinder 69.

When the sand carrier 42 is in its forward position in alignment with the air chamber 28, the operator may automatically openate the core box clamping mechanism and the blowing mechanism of the core-making machine. This is accomplished by simultaneously pressing the two start buttons 208 and 209 of the electric control means shown in Fig. 10. When the two start buttons 208 and 209 are depressed, current flows through the 'conductor 210, "the switch 204, conductor 21 1, contact 212, and conductor 213 to the solenoid 1214 of the solenoid valve 196 which controls the openation of the core box clamping mechanism.

When the core box is in clamped position, the switch 215 closes, permitting current to flow from the conductor 211 through the conductor .216, switch 215, and conductor 217 .to the time delay unit 218. When the time delay unit 218 starts operating, the switch 224 closes, permitting current to flow *from the time delay unit 218 through the conductor 225, switch 224, conductors 226 and 21 1, contact 212, and conductor 213 to the solenoid 214 thereby keeping the solenoid valve 196 energized when the start buttons 208 and 209 are released.

When the time delay unit 218 times out, the switch 227 closes permitting current to fiow from the time delay unit 218 through the conductor 225, switch 227, conductors 228 and 229, contact 230, and conductor 232 to the solenoid 233 operating the solenoid valve 200 which operates the blow valve 27 permitting air to blow into the sand carrier 42 and core-box sections 46 and 49. Simultaneously, current flows from the conductor 228 to the time delay unit 234.

When the time delay unit 234 times out, the switch 13... 236 operates closing contact 235 thereby permitting current to fiow through the conductors 210 and 237, contact 235 and conductor 238 to the relay 231. This causes the contacts 212 and 230 to open, whereupon the blowing operation ceases and the lift cylinder 53 moves to the bottom of its stroke thereby separating the halves of the core-box 46 and 49. When the cylinder 53 starts its downward movement, switch 215 opens whereupon current ceases to flow to the time delay units 218 and 234 permitting units 218 and 234 to reset themselves. When the time delay unit 234 resets itself, the relay 231 opens, causing the contacts 212 and 230 to close for the start of the next cycle.

In operation, the operator manually operates the sand carrier refill valve lever 110 to move the carrier into alignment with the sand hopper 25 whereupon the vibrator 116 operates causing sand to move downward from the hopper 25 into the sand carrier 42. When the sand carrier 42 is filled with sand, the operator moves the sand refill valve lever 110 so as to move the carrier forward into alignment with the air chamber 28. The operator then may automatically operate the core-making machine by depressing the start buttons 208 and 209 which starts the clamping and blowing cycle. Successive cores are made by the operator until there is no longer any sand in the sand carrier 42. The operator may then repeat the above operations.

From the foregoing, it is apparent that the present invention provides a control mechanism for a coremaking machine which is compact, simple in construction, easily adjustable for automatic, semi-automatic, or manual operation, has a number of improved safety features, and materially speeds up the manufacture of any number of cores.

Various features of the invention which are believed to be new are expressly set forth in the appended claims.

We claim:

1. In a core-making machine having a sand transfer mechanism, a core-box clamping mechanism, and a blowing mechanism, said mechanisms having a relative movement in a predetermined sequence, a means for controlling such movements comprising a source of pressure air, a plurality of conduits connecting said source of pressure air to said mechanisms, a plurality of valves in said conduits which are adjustable to a plurality of arrangements for changing the path of flow of air through said conduits from said source of pressure air to said mechanisms, manually operable means in said conduits for controlling said mechanisms in said sequence when said valves are adjusted to a first arrangement, automatically operated means in said conduits for controlling said mechanisms in said sequence when said valves are adjusted to a second arrangement, and a portion of said manually operable means being operable for controlling said sand transfer mechanism and a portion of said automatically operated means being operable for controlling said core-box clamping mechanism and said blowing mechanism in said sequence when said valves are adjusted to a third arrangement.

2. In a core-making machine having a sand transfer mechanism, a core-box clamping mechanism, and a blowing mechanism, said mechanisms having a relative movement in a predetermined sequence, a means for controlling such movements comprising a source of pressure air, a plurality of conduits connecting said source of pressure air to said mechanisms, a plurality of valves in said conduits which are adjustable to a plurality of arrange ments for changing the path of flow of air through said conduits from said source of pressure air to said mechanisms, manually operable means in said conduit for controlling said mechanisms in said sequence when said valves are adjusted to a first arrangement, automatically operated means in said conduits for controlling said mechanisms in said sequence when said valves are adjusted to a second arrangement, electrical means connected to said automatically operated means for operating the same, and a portion of said manually operable means being operable for controlling said sand transfer mechanism and a portion of said automatically operated means being operable for controlling the movement of said core-box clamping mechanism and said blowing mechanism in said predetermined sequence when said valves are adjusted to a third arrangement.

3. In a core-making machine having a sand transfer mechanism, a core-box clamping mechanism, and a blowing mechanism, said mechanisms having a relative movement in a predetermined sequence, means for controlling such movements comprising a source of pressure air, a plurality of conduits connecting said source of pressure air to said mechanisms, a plurality of valves in said conduits which are adjustable to a plurality of arrangements for changing the path of flow of air through said conduits from said source of pressure air to said mechanisms, manually operable means in said conduits for controlling said mechanisms in said sequence when said valves are adjusted to a first arrangement, automatically operated means in said conduits for controlling said mechanisms in said sequence when said valves are adjusted to a second arrangement, electrical means connected to said automatically operated means for operating the same, a portion of said manually operable means being operable for controlling said sand transfer mechanism and a portion of said automatically operated means being operable for controlling the movement of said core-box clamping mechanism and said blowing mechanism in said predetermined sequence when said valves are adjusted to a third arrangement, and safety means in said conduits for preventing the manual operation of said mechanisms out of said predetermined sequence.

4. In combination in a core-making machine having an air operated sand transfer mechanism, core-box clamping mechanism and blowing mechanism, said mechanisms having a relative movement in a predetermined sequence, a mechanism for controlling such movements comprising a source of pressure air, a plurality of conduits con necting said source of pressure air to said air operated mechanisms, a plurality of two-way selector valves and a plurality of by-pass valves in said conduits, said selector valves and said by-pass valves being adjustable to a plurality of arrangements for changing the path of flow of air through said conduits from said source of pressure air to said air operated mechanisms, manually operable means connected in said conduits for regulating the flow of pressure air to said air operated mechanisms when said selector valves and said by-pass valves are adjusted to a first arrangement, automatically operated means connected in said conduits for regulating the flow of pressure air to said air operated mechanisms when said selector valves and said by-pass valves are adjusted to a second arrangement and a portion of said manually operable means being operable for regulating the flow of pressure air to said sand transfer mechanism and a portion of said automatically operated means being operable for regulating the flow of pressure air to said core-box clamping mechanism and said blowing mechanism when said selector valves and said by-pass valves are adjusted to a third arrangement.

5. In combination in a core-making machine having an air operated sand transfer mechanism, core-box clamping mechanism and blowing mechanism, said mechanisms having a relative movement in a predetermined sequence, a mechanism for controlling such movements comprising a source of pressure air, a plurality of conduits connecting said source of pressure air to said air operated mechanisms, a plurality of two-way selector valves and a plurality of by-pass valves in said conduits, said selector valves and said by-pass valves being adjustable to a plurality of arrangements for changing the path of flow of air through said conduits from said source of pressure air to said air operated mechanisms, manually operable means connected in said conduits for regulating the flow of pressure air to said air operated mechanisms when saidselector valves and said by-pass valves are adjusted to a first arrangement, automatically operated means connected in said conduits for regulating the flow of pressure air to said air operated mechanisms when said selector valves and said by-pass valves are adjusted to a second arrangement, electrical means connected to said automatically operated means for operating the same, and a portion of said manually operable means being operable for regulating the flow of pressure air to said sand transfer mechanism and a portion of said automatically operated means being operable for regu-v lating the flow of pressure air to said core-box clamping.

mechanism and said blowing mechanism when said selector valves and said by-pass valves are adjusted to a third arrangement.

6. In combination in a core-making machine having an air operated sand transfer mechanism, core-box clamping mechanism, and blowing mechanism, said mechanisms having a relative movement in a predetermined sequence, a mechanism for controlling such movements comprising a source of pressure air, a plurality of conduits connecting said source of pressure air to said air operated mechanisms, a plurality of two-way selector valves and a plurality of by-pass valves in said conduits, said selector valves and said by-pass valves being adjustable to a plurality of arrangements for changing the path of flow of air through said conduits from said source of pressure air to said air operated mechanisms, manually operable means connected in said conduits for regulating the flow of pressure air to said air operated mechanisms when said selector valves and said by-pass valves .are adjusted to a first arrangement, automaticallyoperated means connected in said conduits for regulating the flow of pressure air to said air operated mechanisms when said selector valves and said by-pass valves are adjusted, to a second arrangement, electrical means connected to.

said automatically operated means for operating the same, said electrical means being adjustable to a plurality of. arrangements, said automatically operated means being fully operated by said electrical means when said electrical means are adjusted to a first position, and a portion of said manually operated means being operable for regulating the flow of pressure air to said sand transfer mechanism and a portion of said automatically operated means being operable for regulating the flow of pressure air to said core-box clamping mechanism and said blowing mechanism when said selector valves and 16'? said by-pass. valves vareadjusted to a third arrangement, only said.,portion of said automatically operated means being operated Whensaid electrical means are adjusted to asecond position, and safety means in said conduits for preventing the manual operation of said air operated mechanisms out of ;said predetermined sequence.

7. In-combination in a core-making machine having an air operated sand transfer'mechanism, core-box clamping mechanism andblowing mechanism, said mechanisms having a relative-movement in apredetermined sequence, a mechanism for controlling such movements comprising a source of pressure air, a plurality of conduits connecting said source of pressure air to said air operated mechanisms, a;.plurality of two-way selector valves and a pluralitytof by-pass valves in said conduits, said selector valves and said by-pass valves being adjustable to a plurality of arrangements for changing the path of flow of air throughsaid conduits from said source of pressure air to said-air operated mechanisms, manually operable means connectedin said conduits for regulating the flow of pressure air to said air operated mechanisms when said selector valves and said by-pass valves are adjusted to a, first arrangement, automatically operated means .connected in said conduits for regulating thefiow of pressure airtosaid air.operated mechanisms when said .selector valves and saidby-pass valves are adjusted to a second arrangement, electrical means connected to said automatically. operated means for operating the same, and a portion of'said manually operable means being operable for regulating the flow of pressure air to said sand transfer ;mechanism and a portion of said automatically. operated means being operable for regulatingthe flowof. pressure air to said core-box clamping mechanism and said blowing mechanism when said selector valves and said-by-pass valves are adjusted to a third arrangement, and safety-means in. said conduits for preventing the manual operation of said air operated mechanisms out of said predetermined sequence.

References Cited in the file of this patent UNITED STATES PATENTS 1,480,749 Demmler Jan. 15, 1924 1,563,156 Burman Nov. 24, 1925 1,801,654 Blood Apr. 21, 1931 2,259,768,- Nayloretal Oct. 21, 1941 2,274,191 Davis Feb. 24, 1942 2,547,081 Lund Apr. 3, 1951 2,615,302 Camerota Oct. 28, 1952 

1. IN A CORE-MAKING MACHINE HAVING A SAND TRANSFER MECHANISM, A CORE-BOX CLAMPING MECHANISM, AND A BLOWING MECHANISM, SAID MECHANISMS HAVING A RELATIVE MOVEMENT IN A PREDETERMINED SEQUENCE, A MEANS FOR CONTROLLING SUCH MOVEMENTS COMPRISING A SOURCE OF PRESSURE AIR, A PLURALITY OF CONDUITS CONNECTING SAID SOURCE OF PRESSURE AIR TO SAID MECHANISMS, A PLURALITY OF VALVES IN SAID CONDUITS WHICH ARE ADJUSTABLE TO A PLURALITY OF ARRANGEMENTS FOR CHANGING THE PATH OF FLOW OF AIR THROUGH SAID CONDUITS FROM SAID SOURCE OF PRESSURE AIR TO SAID MECHANISMS, MANUALLY OPERABLE MEANS IN SAID CONDUITS FOR CONTROLLING SAID MECHANISMS IN SAID SEQUENCE WHEN SAID VALVES ARE ADJUSTED TO A FIRST ARRANGEMENT, AUTOMATICALLY OPERATED MEANS IN SAID CONDUITS FOR CONTROLLING SAID MECHANISMS IN SAID SEQUENCE WHEN SAID VALVES ARE ADJUSTED TO A SECOND ARRANGEMENT, AND A PORTION OF SAID MANUALLY OPERABLE MEANS BEING OPERABLE FOR CONTROLLING 